If I were to donate to EFF, I'd want to do so anonymously. Like very anonymously. So bitcoin is an interesting option - depending on how easy it is to get bitcoin anonymously. I don't want other charities or political organisations to hound me for years afterwards. And I don't want a donation to be used against me if/when some overblown official in my country decides that EFF is a terrorist organisation.

I found the humble bundle is a good way of donating to EFF, because that way at least it looks like a game purchase rather than a donation. If I were interested in donating of course.